good so i hope that was helpful and uh we'll move forward now from wave direction uh with the rubber ducky and those little circles into a new topic all about this wave train idea so wave train is kind of like a set of waves so four waves here and it's a very interesting thing that um not a lot of people know i feel like about waves so how they move across the surface of an ocean is they slowly transfer their energy between each each wave okay so if you look here here's the leading wave wave one and there's two three four behind it okay and it's moving from left to right wave one will actually die out and the energy in this wave one is transferred into circular orbital motion that helps wave two and it actually creates a wave five okay so there was no wave five here but wave one died out and created wave five and then so on and so forth wave two dies out and creates wave six and then wave four dies out and creates wave seven so it's almost like two steps forward one step back okay and so however fast an individual wave is moving the actual train of waves so this set of four waves four waves four waves four waves those four waves are moving at half of the wave speed that a single wave is moving that's a big takeaway here okay so the group speed right or the wave train speed is one half that of the individual wave hard to get your mind potentially wrapped around that but they do a good job once again in that video um that you're going to have an assignment on um from walter monk called waves across the pacific so make sure you do that um and watch that video and fill out that worksheet okay that's gonna be an assignment okay moving on if we take a look at this in depth here we go here's our first set of waves as they move from left to right it's actually transfer wave 1 dies out and wave 5 is created and then we can continue on where wave 2 dies out and wave 6 is created and then wave three dies out wave seven is created once again this causes the group speed to be one half that of the individual wave so make sure you answer that and know that okay that's a good test question all right now the last thing that i want to get through to you here is uh back at the first page of your worksheet we talked about um how we were gonna learn a little bit more about deep water waves and shallow water waves so go back to the first page of your worksheet and we're gonna fill out the definition of a deep water wave versus a shallow water wave okay so here's an idea of we've got waves this is the depth this is the depth of the bottom okay it slowly gets shallower and shallower and shallower out to where we are here on the beach right so here we are standing not next to a cliff remember we're out away from the cliff so if there's a cliff here we're going to set up our umbrella way out here okay so take a look here this zone straight down to here all right all this area focus in on the wave base this wave base right it's equal to one half the wave length and i want you to remember this because your wave base determines if it's a shallow water wave or a deep water wave okay so a deep water wave is a wave in which the wave base is not touching the bottom of the the ocean okay so this brown area or tan color here this is not this is the bottom of the ocean and these waves here this is representing the wave base so how far down that orbital motion goes it's not touching the bottom of the ocean but right here is where it actually does so here's where that distinction happens okay so out here these are deep water waves they've got constant wavelengths these are deep water waves where the wave base is not touching the bottom and then from here forward towards the shore these are shallow water waves okay because the waves start with their wave base their wave base starts touching the bottom of the ocean starts dragging along and actually slows them down so your wave speed decreases as you go into shallower and shallower water and your wavelength shortens so it's kind of like cars coming up to a red light and they're moving fast out here so this is the highway all the cars are moving fast they're spaced apart evenly and then the red light is all the way up here right so waves start to slow down as they approach that red light where they're gonna break and the cars get closer and closer together and they get slower and slower that's what i'm talking about okay so you could imagine it as highway speeds out here coming into a red light with your car and your cars get stacked closer and closer together your wavelength shortens and your speed slows down so your wave speed decreases velocity decreases right so that's kind of how things start to slow down now because this energy here is your wave base is hitting the bottom it actually increases the wave height as well until they break all right and that's kind of oh look there's that little barrel zone right there okay so that's your difference deep water waves the wave base is not touching the bottom shallow water waves your wave base is touching the bottom okay makes sense if you got questions please let me know um i'd be happy to go through it again with you and make sure you fill out that diagram okay so we'll go from there and and now we're gonna we're gonna check the cams i'm gonna look at live footage of um some local waves and talk to you about all these features that we just covered okay all right see you soon here we go to the camps okay so here we are um can anyone guess where this is yeah hopefully you know this is uh swami's so this is in downtown encinitas and uh here's a couple pieces of reef right making their way out into this nice wave out here and today it's actually very very stormy so this is kind of the storm is on us right so here you have all those different waves different periods different wavelengths all occurring at the same time kind of like how it was in lake superior when i showed you that clip from weird waves so this is a look at this if we thought of you know our wave periods they'd be all mixed up our wavelengths would be all mixed up and our wave speeds would all be mixed up one thing i want you to take away from this though is that within this area we're all talking about shallow water waves all throughout here whereas out way out here in the deeper deeper water these are deep water waves what distinguishes those two well it's all about whether or not the wave base which is equal to one-half the wavelength is touching the sea floor or not if it's outside of that meaning it's deeper water than half the wavelength or the wave base then it's a deep water wave if it's touching the sea floor the wave base then it's a shallow water wave let's take a look at another spot as well we'll head over to pleasure point and here we are up in santa cruz now and uh what you see here is much different conditions right you're away from the storm this is looks like a nice high pressure where where we live is a low pressure currently in this moment and uh you see that the waves are actually a lot cleaner right and a lot more organized now these here where these surfers are these are shallow water waves out here deep water waves one key factor here is that your wavelengths are longer out here right they're shorter here your wave speeds are faster out here in deep water your wave speeds are slower here that's why we can catch those waves but your period it stays the same so your period in a deep water wave and your period here in a shallow water wave that remains constant that is a key factor that i want you to remember okay so um wave period stays the same wave length gets shorter as you move into shallower water wave speed decreases as you move into shallower water and your wave height actually increases as you move into shallower water and this is all because the wave base is interacting with the sea floor so yeah another way to talk about um wave period if you didn't quite know right is imagine standing out here um right or imagine being a buoy right here like these surfers right you would be sitting here and each time a wave went past you that's how you would time it right between consecutive crests so i would start my watch when a wave came and hit me so right now i'd click my timer i'd be sitting here standing still waiting and then solid but surely here comes another wave and that wave now is hitting at the same spot now okay so that's your wave period it's a time right so that was like 10 seconds or so 12 seconds so that's a 12 second period your period stays the same from a deep water wave to a shallow water wave great so let's uh head back into the classroom