1. Amplitude Wavelength Frequency.
Amplitude is the distance between the resting position and the top and bottom of the waves. You can measure this distance.
Frequency is the amount of waves that happen in a second. Can be measured by counting the waves throughout one second. The waves start and end in the middle.
One wave
Wavelength how far away the waves are from each other. Usually they are measured at the bottom and top of the wave. The distance between the waves is called wavelength. This can be measured by measuring the space between the waves.

2. Law of Reflection and Periscopes
The law of reflection says that the angle of incidence and the angle of reflection, always have to have the same (equal) angle. The angle of incidence is the angle in which the light hits something and the angle of reflection is the angle it bounces off of something. The law of reflection is what makes a periscope work.
A periscope works thanks to the law of reflection. Because the angle of incidence and the angle of reflection have to be the same, the light can travel through the periscope into your eye.
As you can see in the diagram, the angle of incidence and angle of reflection, both have the same angle degree in this case 45 degrees. This can be worked out because when you look at the diagram, you can recognize right angles and the half of 90 is 45.

3. Concave and Convex Lenses
A convex lenses, bends towards the outside as shown in the picture. Instead the concave lenses, is the exact opposite, it bends inwards just like a cave. The two different lenses, also bend light in different directions.

4. Rainbows
How and why do we get a rainbow? A rainbow is formed from light that goes through a prism and gets split into different colors. A rainbow is created because the light of the sun gets split through the rain and we obtain different stripes of color; rainbow.

5. Why do we see objects that don’t produce light?
We can see objects that do not produce light, because light can bounce of this object and into your eye which allows you to see it. A object doesn’t have to create light for us to be able to see it.

6. Difference between reflection and refraction
Reflection is when light bounces of an object at the same angle following the law of reflection (see different slides) for example reflection is used with a mirror. Refraction is when light gets bent into a different direction and does not follow the law of reflection anymore. For example when you have a coin in a bowl stand far away so you cannot see the coin anymore and then you fill the bowl with water, you will start seeing the coin because the light gets refracted into your eye.