science blog- week of 9/21/O9

In the beginning of this week we learned that on one spot on the lightbulb, light is being emitted in all different directions. We learned this by doing an experiment. Our experiment was putting the tin foil over the lightbulb and then a piece of cardboard with a small hole in it. When we looked at the ceiling, we couldn't see a small dot, we just saw a lot of light.

We also learned why and how we could see a marker. There were a few hypothesis. One was that you can see the marker if you concentrate on it. We proved that wrong because everyone in the class could see it, even if they weren't concentrating on it. Another hypothesis was that light rays bounce off the marker and into someone's eyes. This hypothesis was partly true, because light rays DO bounce off the marker, but then they go in every direction, so anyone can see the marker. This is important because now we know how we see everyday objects.

This week, we also learned why a candle's shadow is upside down if you hold it up to a small hole in a piece of cardboard. It is because the top rays from the candle go down to get through the hole, and then bottom rays go up, so then on the other side of the hole, the candle's shadow is upside down. Related to this, we also spoke about how cameras work. They work similar to the candle//cardboard experiment that we did. The image that you take a picture of is like the candle. The top rays have to go throught the bottom of the camera lens, and then bottom rays have to go through the top. For digital camera, the camera flips the image before you see it. And for non-digital cameras, the film is devolped upside down, and then we just flip it over. This is important so that we know how everyday items work and why shadows are the way they are.